Better Apples, Better Production—Starting at the Roots
Rootstock, the part of the tree below ground, is a key component of the high density, yield-and labor-efficient production system for apples. Currently, the most widely used rootstocks for commercial apple production in the United States are susceptible to replant disease and soil abiotic stresses, leading to an estimated annual loss of $300 million to the apple industry. Fruit quality problems cause additional losses particularly for high value cultivars such as Honeycrisp, with rates of loss as high as 50 percent in some regions. To remain successful and competitive and to meet customer demand, the United States apple industry needs new roots.
Lailiang Cheng and Terence L. Robinson, Integrative Plant Science, and Bradley J. Rickard, Dyson School of Applied Economics and Management, want to accelerate the development, evaluation, and adoption of improved apple rootstocks. With collaborators at the United States Department of Agriculture, University of Idaho, and Utah State, Michigan State, and Washington State Universities, they are focusing on both evaluating new rootstock candidates and identifying genetic markers for difficult-to-phenotype complex root traits. Attention to these traits—such as replant disease tolerance, nutrient uptake and partitioning (especially calcium), and low or high soil pH and salinity—will improve tolerance of rootstocks to biotic and abiotic stresses and the quality of high value cultivars such as Honeycrisp.
With better rootstocks, new cultivars, and region-specific management protocols, the team expects marketable yields to increase by 20 to 25 percent. The project also includes extension efforts to all United States apple growers by using new strategies (Twitter, eXtension, Webinars) as well as tried-and-true outreach approaches. The entire apple industry—including nurseries, producers, and packers—will benefit from this project’s outcomes.